Here, in France, you can buy "Alcool à brûler" in any supermarket. It consists of 90 to 95% ethanol with 5 to 10% methanol. Both are highly volatile and leave no residue making it very good for cleaning.
equivalent here is rubbing alcohol.Composition is different though its pretty good but im sure that there is something else in it , it feels slightly oily after evaporationThe french type cannot be imported to the uk without a licence, i tried once.
So you think the 99% concentration has a noticeably greater solvent power than the 91%? It would be interesting to see a blind test.
The key thing is that it leaves less water behind.
Citation?But... the 99% starts out with less water in it. So even if the alcohol evaporates more quickly, it reaches dynamic equilibrium at 91% and continues to evaporate at 91%, but it has reached that point more quickly.
I wouldn't be surprised if some other solvent would be better overall for cleaning the gunk off of PCBs.